Stoker



April 1945 I R. L. BEERS 2,373,44

STOKER Filed Oct. 12, 194 2 4 Sheets-Sheet 1 INVENTOR.

I ROYCE L.BEERS ATTORNEYS April 10, 1945. R L BEERS 2,373,448

STOKER Filed Oct. 12, 1942 4 Sheets-Sheet 2 INVENTOR- ROYCE L. BEERS BY ATTORNEYS R. L. BEERS STOKER April 10, 1945.

4 Shets-Sheet 3 Filed Oct. 12, 1942 INVENTOR.

ROYCE L.BEERS ATTORNEYS R. L. BEERS April 10, 1945.

STOKER I Filed Oct. 12, 1942 4 Sheet s-Sheet 4 INVENTOR.

ROYCE L.-BEER S ATTORNEYS Patented Apr. 10, 19455 STOKER Royce L. Beers, Birmingham, Mich., assignor to Detroit Stoker Compan poration of Michigan y, Monroe, Mich., a cor- Application October 12, 1942, Serial No. 461,761

. 6 Claims.

, The invention relates to stokers of that. typ in which the fuel i first introduced and elevated in a retort and then fed laterally therefrom over grate bars. To facilitate this lateral feed it has been customary to reciprocate certain of the grate bars, leaving stationary grate bars intermediate the same. Also where, as usual, the retort is in the center of the furnace, with the laterally extending grate bars on opposite sides thereof, it has been usual to reciprocate the grate bars oppositely on opposite sides of the retort. One serious objection to this construction is that when the bars on opposite sides of the retort are simultaneously moved towards each other, there is a tendency to compress the fuel lying therebetween, placing severe strains on the operating mechanism. It is therefore one of the objects of the instant invention to avoid this difficulty.

The fuel on the grate bars is gradually advanced toward the ash dump, and with certain constructions of stoker, rocking segmental grates are arranged at the ends of the bars for facilitating the ash discharge. Usually these rocking grates operate simultaneously with the reciprocating rate bars and with substantially the same amplitude of movement. However, I have found it desirable under certain conditions'to leave the rocking grates stationary during the reciprocation of the grate bars, while at other times it is desirable to oscillate the rocking grates while the reciprocating grate bars are stationary. At still other times it may be advantageous to simultaneously move the reciprocating bars and the rocking grates, but with different degrees of movement. It i another feature of my invention to provide for such varied operations.

Another feature of my invention relates to means for varying the degree of opening between the rocker grates and the adjacent furnace wall or wall tuyere. A further feature is a novel construction of means for taking care of expansion. The invention therefore consists in these various features and other improvements, as more fully hereinafter described.

In the drawings:

Figure 1 is a vertical cross section improved stoker;

Figure 2 is a diagrammatic plan view thereof;

Figure 3 i a view similar to a portion of Figure 1, showing a modified construction;

Figure 4 is a vertical longitudinal section on line 4-4, Figure 1; a

Figure 5 is a similar section on line ure 1;

through my 5-5, Fig- Figure 6 is a side elevation illustrating a portion of the operating mechanism;

Figure 7 is a cross section on line l- -l, Figure 6;

Figure 8 is a front elevation of the mechanism for operating the rocking grates; and

Figure 9 is a section on line 9-9, Figure 8.

As shown in Figure 1, the retort A extends longitudinally in the center of the furnace and is provided with the usual fuel feed (not shown). B and B are grate bar extending laterally upon opposite sides of the retort, being supported at their inner ends on flanges A of the retort, and

at their outer ends upon channel beam C and C. The grate bars are assembled to form groups D, D, etc. and E, E, etc. Each group contains aplurality of bar rigidly secured to each other, with the groups D, D arranged on one sde of the retort and the groups E, E on the opposite side thereof. Extending longitudinally beneath the bars and on opposite sides of the retort are rock shafts F and F, on which are mountedrock arms G and G. These rock arms correspond in number to the groups D, D and E, E, and extend downwardly from the shafts, being cross connected to each other by connecting rods H which pass beneath the retort. To secure the rock arms on the shafts, eachis prtlvided with a flanged cap portion G bolted to similar flanges on the lower portion of the arm. The cap portions are provided with upwardly extending fingers G rounded to engage segmental recesses in the lower portion of the bars B, B in .each group. Thus, if an arm G on one side of the retort is rocked about the axis of it shaft, it will simultaneously impart movement in the same direction to the bars B and B on opposite sides of the retort. The rock arms G, G are actuated by the rock shafts F and F, but in the corresponding groups only the arm on one side of the retort are keyed to the shaft, those on the opposite side being freely revoluble thereon. In alternate pairs of groups the arms are keyed to opposite, shafts so that by rocking the shafts oppositely, the bar in one pairof groups will be moved in the opposite direction from the bars in an adjacent pair of groups. However, the bars of the groups in each pair always move simultaneously in the same direction With the construction as thus far described, it will be obvious that in the reciprocation of the grate bars there will be no compressive stresses transmitted to the fuel supported thereon. Consequently, the strain upon the operating mechanism is verymuch less thanwherethe opposed bars on opposite sides of the retort are simultaneously moved towards each other. On the other hand, as alternate pairs of groups are simultaneously moved in opposite direction, the feeding of the fuel downward over the grate bars on each .side of the retort is accomplished.

As shown, in Figure 1, the

yond the outer ends of the bars B and B.

the construction shown in Figure 3, there are stationary grate sections J beyond. the reciprocating grate bars B, and an ash dump grate K beyond the member J. In each of these constructions the operation of the reciprocating groups- D, D, E, E is the same, and each has the advantage of avoiding compressive stresses on the fuel.

With the type of construction illustrated in Figure 1, it has been customary to acmate the rocker grate I by connecting the same to the reciprocating grate bars. This necessitates imparting the same degree of movement to each, which, as abcvedescribed, is not always desirable. To permit independent movement of the reciproeatin and rocking grates, I provide a suitable 'actuatingmechanism therefor, such as the following: As illustrated in Figure 6, the actuating mechanism is arranged in front of the furnace, being preferably operatedby a reciprocating ram (not shown). To this ram is connected a member L having internal helical grooves M therein w engaging corresponding helical flanges M of a rctary shaft M. Thus, durin the reciprocation of the ram the movement of the memberL therewith will impart a rota-tive movement to the shaft M in one direction during the forward stroke and in the opposite direction during the return 'stroke.- The member M has at its inner'end a flange M to which is connected, preferably through the medium of shear pins M a disc N,

which in turn has a lost motion coupling connection with a head N on oneof the rocker shafts jecting between a pair of spaced lugs N on the member N. There is also an adjustable screw N engaging acorrespondingly threaded bearing in the log N and projecting therefrom to bear against one of the lugs N When the screw completely retracted, the free angular movement of the lug N is equal to the full angular movement of the member N, so that no. motion is communicated to the member N. On the other hand, where the screw N is fuliy projected, it will take up all of the lost motion, so that both members N and N will have an equal amplitude. of movement. It will, therefore, be understood that the angular movement of the shafts F and F i may be varied between zero and the full angular movement of the members M and For actuating the rocker grates I and I, each of the members N is provided with .a crank pin N which engages a connecting rod 0 leading to arock arm P on a polygonal rock shaft Q. On this rock shaft are sleeved. upwardly extending rock arms Q having rounded portions at their upper ends engaging segmental bearings Q in the segmental rocker grates I and I. These segmental rocker grates are connected at their lower ends to links R which extend at such an angle to the rock arms Q as to impart a substantially vertical movement to the outer ends of the grate during the substantially horizontal movement of the inner ends thereof. Tuyere members S projecting outward from the furnace wall S extend in proximity to the outer ends of the rocker grates I, leaving only a comparatively narrow space therebetween through which the ash is discharged.

With the construction just described, the rockingmovement of the member N is transmitted through the connecting rod 0 to the rock arm P which, by rocking the shaft Q, imparts a rocking or oscillatory movement to the grates I or I. As the radial length of the rock arm P is substantially equal to that of the radius of the crank pin N the amplitude of angular movement of the grate will correspond to that on the members M and N, I have, however, provided a lost motion connection by formin the rod O in two sections 0 and 0 which have a telescopic engagement with each other. The outer section 0 has slots 0 in the opposite walls thereof, while the inner section is provided with a series of apertures O with which a coupling pin 0 is alternatively engaged The arrangement is such that by changing the pin 0 from one aperture to another, the amount of lost motion may be varied from zero to that equal to the full movement of the member 0'. This permits of imparting any desired amount of movementto the rocker grates I and I up to the full. angular movement of the member N, or, if desired, said rocker grates may be allowed to remain stationary.

' It may be desirable to vary the spacing between the rocker grates I, I and the tuyere members S for different conditions in the operation of the stacker. This I have provided for by pivoting the links R upon rock arms R which are mounted on a polygonal shaft R .At the outer end of the shaft R there is an arm R which engages a screw R By adjusting this screw in its threaded bearing R the angle of the arm B may be altered, which in turn correspondingly changes the angle of the :arm .R. Thus, by'rocking the arms R, downwardly, the space between the rocker grates and the tuyeres S'may be enlarged, while an adjustment upwardly of the :arms R will decrease this space.

When the stoker is under heat, the expansion of the grate bars B and B will be sumcient to cause aconsiderable relative movement of the ends of the series. I Such movement can be prevented by providing space between the individual bars, but this is objectionable .as it alters the amount of air permitted to pass through the grates under different conditions of heat. Another method which has heretofore been used is to undercut the furnace walls at one or both ends of the series of grates, permitting movement of the end members into or out of the recesses during expansion and contraction, Such construction is objectionable in that it-renders detach-'- ment and replacement of these'end members difiicu-lt, generally requiring the cutting away of the walls. One of the features of my invention is an improved construction of expansion means winch is free from any recess in the furnace wall so as to be easily disengageable. As illustrated in Figure 4, the furnace wall T has embedded therein a metallic tuyre member T, with its inner face flush with that of the wall. 'I is an angular member having one flange abutting against the surface of the member T and its other flange extending into the furnace chamber. A second angular member T is arranged with one flange abutting against the end grate bar section D and the other flange overlapping the corresponding flange of the member T Between the members T T is a resilient assembly U including a pair of arms U, U together forming a Y- shaped structure. The lower end of the arm U is connected to a rod U which passes through an aperture in the arm U and has sleeved on its projecting portion a spring U abutting against an adjustable nut U engaging a threaded portion of the rod. The upper ends of the arms U,

U have hook portions U which engage recessed lugs U on the members T T thereby suspending the assembly U therefrom. In assembling the structure the members T T and the resilient assembly U can be easily installed, as none of these parts enters a recess in the furnace wall. When the stoker is under heat the expansion of the series of grate bars will cause a relative movement of the members T T which is permitted by the compression of the spring U On the other hand, when the furnace cools, this spring will separate the members T T to correspond with the contractionof the grate bars. During such movement the parallel flanges of the members T *1 remain in overlapping engagement so as to prevent any passage of air therebetween.

What I claim as my invention is:

1. In a stoker the combination with a central fuel feed, of grates extending laterally on opposite sides of said feed formed of alongitudinal series of separate sections, and means for laterally reciprocating said sections with the aligned sections on opposite sides of said fuel feed simultaneously moving in the same direction, and adjacent sections of the series simultaneously moving in opposite directions.

2. In a stoker the combination with a retort,

rate sections, rock shafts extending longitudinallybeneath said grates on opposite sides of said retort, rock arms sleeved on said rock shafts and extending into engagement withthe respective grate sections to reciprocate the same, the rock arms for alternate sections of the series being respectively rotatably fixed and rotatably free on their shafts, and the rock arms for aligned sections on opposite sides of the retort being respectively fixed and free on their shafts, cross connections between the ali ned fixed and free rock arms, and means for simultaneously rocking said rock shafts in opposite directions whereby the aligned sections of each pair are simultaneously moved in the same direction and the aligned sections of adjacent pairs are simultaneously moved in the opposite direction.

4. In a st cker the combination with a retort, of grates extending laterally on opposite sides of said retort formed of a longitudinal series of pairs of separate sections, rock shafts beneath said grates on opposite sides of said retort, rock arms on said rock shafts having upwardly extending portions for engaging the respective grate sections to reciprocatethe same, and also portions extending downwardly to below said retort, connecting rods between the aligned downwardly extending portions of the arms on said shaft, means for rotatably connectingsaid arms to the shaft in alternate sections of longitudinal series of grates, leaving the intermediate arms rotatably free onthe shaft and with the fixed arms on one shaft aligned with the free arms of the other shaft, and means for rocking said shafts simultaneously in opposite directions, whereby reciprocatory movement is imparted to said grate sections with the aligned sections of each pair moving simultaneously in the same direction and the aligned sections of adjacent pairs moving simultaneously in the opposite direction.

5. In a stoker the combination with a retort, of grates extending laterally on opposite sides of said retort, rock shafts beneath the grates on both sides of the retort, rock arms sleeved on said rock shafts to extend into engagement with the respective grates to reciprocate the same and also extending downward to below said retort, one of said rock arms being coupled to its rock shaft, a rod connecting the lower ends of said rock arms and passing beneath said retort, and means for rocking the rock shaft to which the rock arm is coupled to oscillate the latter and to communicate movement in the same direction to the rock arm and grate on the opposite side of the retort.

6. In a stoker, the combination with a central fuel feed of grates extending laterally on opposite sides of said feed formed of lon itudinal series of separate sections, and means for laterally reciprocating said sections with the aligned sections on opposite sides of said fuel v feed simultaneously moving in the same direction, certain of said aligned sections moving in one direction and others simultaneously moving in the opposite direction.

ROYCE L. BEERS. 

